The present invention relates to deep tillage tools for agricultural implements such as rippers, and more specifically to a ripper point for such an implement.
In the past, straight shank rippers have been used to fracture soil without substantial destruction of the soil surface. These rippers were designed to eliminate soil compaction without inverting soil layers or significantly disturbing the surface residue. Farmers want to have the root growth and water movement benefits from ripping the soil without being penalized with a loose, uneven surface profile in the spring. Ripper points designed to reduce surface profile variability are shown, for example, in U.S. Pat. Nos. 5,437,337 and 5,540,288. The points leave the surface profile substantially undisturbed by not displacing fractured soil. Because the points are designed to leave surface profile generally unchanged, soil fracturing in the compaction layer is at a minimum. With little lateral movement of soil, the fracture zone is only a slot, and water intake and retention properties are compromised. An optimum soil profile for promoting good root growth and water infiltration/retention is also compromised by the limited soil fracture characteristics of points that have little fractured soil displacement.
Many of the presently available ripper points have shallow leading angles which are inadequate to allow tool penetration in hard and/or tight soils. It is not uncommon for operators to adjust the machine out of an optimal level working condition to get the points to enter and remain in the hard or tight soils. This improper adjustment of the machine to achieve better penetration results in deteriorated ripper action and premature point wear. Inconsistent depth can also result from the lack of a vertical force holding the ripper point below the soil compaction layer. Wear life of the points is very short because the penetration ability of the point deteriorates rapidly as wear occurs. Therefore, the points often have to be replaced before they are fully worn away.
A type of tillage sweep shown in U.S. Pat. No. 5,499,686 assigned to Deere and Company includes a wide point having a width of about 2.5 inches and an attack angle of approximately thirty degrees provides for good soil action. The surfaces of the wings have a shallower angle than the point and include leading and trailing edges generally parallel to the ground surface to reduce soil disturbance. However, in some soil conditions, the sweep can cause considerable soil surface change and require an additional pass of a leveling implement such as a field cultivator prior to planting.
It is therefore an object of the present invention to provide an improved deep tillage ripper point. It is a further object to provide such a point which overcomes most or all of the above problems.
It is another object of the present invention to provide an improved ripper point which maximizes soil fracture without creating excessive soil surface disturbance. It is a further object to provide such a point which leaves a relatively level soil surface profile in a variety of soil conditions. It is yet another object to provide such a point which lasts longer than most or all of the previously available points while maintaining its effective working width and soil fracturing and penetrating abilities over substantially all of its wear life.
It is still another object of the present invention to provide an improved deep tillage point for a ripper or similar agricultural implement which has improved penetration ability when compared to at least most previously available ripper points. It is another object to provide such a point which provides necessary vertical force to maintain a consistent depth while working in a compaction layer.
It is another object to provide a ripper point which leaves the surface profile level enough in the fall to eliminate a tillage pass in the spring and even allows for spring no-till farming, if desired. It is a further object to provide such a ripper point that benefits the farmer by making a favorable soil profile for vigorous root growth, by eliminating all or some spring tillage passes, and by increasing water intake and retention capabilities of the soil profile compared to available low surface profile disturbance points.
A ripper point constructed in accordance with the teachings of the present invention includes a narrow leading point portion having a width on the order of 1.33 inches. The top surface of the leading point portion forms an angle in the range of approximately 40-50 degrees with the horizontal when the point is in the field working position. The leading point portion curves rearwardly from a forward edge to an intermediate portion having a top surface which extends at an angle of approximately 15 degrees relative to the horizontal. Wings extend outwardly and slightly downwardly from the intermediate portion and have a top surface which forms a continuation of the top surface of the intermediate portion. The wings also form an angle of approximately 15 degrees relative to the horizontal.
A centrally located vertical fin having a width of approximately half the width of the leading point portion extends upwardly from the leading point portion rearwardly and above the forward edge and forwardly of the leading edges of the wings. The fin projects a small distance above top surface of the leading point portion and then curves upwardly at a location near the forward extremities of the wings and extends rearwardly to a terminating location generally coextensive with trailing edges of the wings. The bottom of the leading point portion extends rearwardly and upwardly from the forward edge at an angle with the horizontal substantially less than that of the top surface of the point portion to define side profile which increases in height from the forward edge to the intermediate portion. The bottom of the intermediate portion extends rearwardly in generally a horizontal attitude to a rearmost point location behind the rear edges of the fin and the wings and is bifurcated to define a shank-receiving area generally behind the rear edge of the fin. The point is attached to the lower end of a shank by bolt structure. The sides of the bifurcated end embrace the sides of the shank and position the rear edge of the fin closely adjacent the front edge of the shank.
The leading point construction helps provide good point ground entry and vertical holding force in the compaction layer. The fin pre-fractures soil and initiates substantial lateral displacement of the soil prior to the soil coming into contact with the wings. The fin also parts the soil before the soil contacts the shank. The wings lift the soil and provide additional fracturing above and outwardly of the point. Soil fracturing in the compaction layer is maximized to provide better fracture percentages for improved water penetration and retention and increased root growth. The point profile establishes the vertical force necessary to maintain a consistent working depth within the compaction layer.
The relatively shallow angle of the wings as compared with many previous points having an attack angle of up to approximately 30 degrees reduces soil surface disturbance in a variety of soil conditions. The narrow point, which is approximately half the width of a typical previously available point, also helps reduce soil surface disturbance. Further reduction of surface disturbance is achieved by the pre-fracturing action of the fin in the compaction layer which substantially reduces violent vertical eruption of the soil when contacted by the wings and the shank. This pre-fracturing action provides substantial initial lateral displacement of the soil, prior to wing contact, and reduces shank wear and drag. The increased lateral displacement compared to most previously available low disturbance points provides an improved soil profile for improved root growth, water infiltration and water retention.
The point is preferably cast from austempered ductile iron for long life. The wings have a parallelogram shape to provide consistent width as the leading edges wear away. The aggressive downward and forward angle of the leading point, in addition to providing excellent penetration of hard or tight soils throughout the life of the point, is designed with a sufficient amount of material to wear out at the same time as the wings, thereby maximizing material utilization and providing consistent ripping performance for the entire wear life of the point. The point design achieves the improved fracturing, depth retention and wear life while still retaining a satisfactory soil surface profile.
These and other objects, features and advantages of the present invention will become apparent to one skilled in the art upon reading the following detailed description in view of the drawings.